1. Field of the Invention
The present invention relates to discontinuous or discrete linear motor systems used to drive transport apparatuses for use in machine tools and industrial machinery, and for driving various other devices.
2. Description of the Related Art
Linear motors have been employed in, for example, a conveyor carriage employed in a physical distributing apparatus or a transport apparatus acting as a machine tool loader (for, example, JP Laid-open Patent Publication No. 63-114887). While the linear motor is available in various types such as, for example, a linear induction motor (LIM), a linear synchronous motor (LSM) and a linear direct current motor, the linear induction motor is employed in a long distance conveyance system. A main type of this linear synchronous motor is one including magnets, installed on the ground side, and a coil side installed movably. The example, such as disclosed in the JP Laid-open Patent Publication No. 2007-82307 listed below, has been suggested in which primary coils of the linear synchronous motor system are partially discretely arranged on the ground side. However, the linear synchronous motor system utilized in such a case is only used in an auxiliary manner at the curved path section, and the linear induction motor is mainly utilized even in such a case. Also, a sensor to detect a position of a mover, such as a needle, a magnet array or a movable coil, is provided relative to only a part of the primary coils.